This most recent round of funding is Dropbox’s third, and was led by BlackRock, Morgan Stanley and T. Rowe Price and Associates, according to venture-capital industry deal book CrunchBase. CrunchBase priced the round at $350 million because Dropbox has reportedly opted to secure another $25 million as part of the round, but will hold the line there, despite having the option to pull down as much as another $125 million.

The timing of Dropbox’s mega raise is notable because it’s just weeks after rival cloud-storage company Box reportedly filed to go public. The Box filing is under wraps thanks to a new regulation passed as part of the JOBS Act -- or Jumpstart Our Business Startups Act -- allowing companies with annual revenue of less than $1 billion to file their initial public offering prospectus with the SEC confidentially. (If you remember, the option for confidential filing was how Twitter got its IPO process started.)

That Box would be going public was not really in question. Nor is it for Dropbox. The Silicon Valley cloud-based storage rivals Dropbox and Box both have scores of venture capitalists nipping at their heels, anxious for a return on their investment. That is, after all, what makes the venture capital industry go round.

As Dropbox and Box stay at each other’s necks, it’ll be curious to see whether being bigger or first is the better IPO strategy.